I wanted to expand my offering of asclepias for Monarch butterflies and other...
I wanted to expand my offering of asclepias for Monarch butterflies and other pollinators and started 10 beautiful plants of A. incarnata (swamp milkweed) early this spring. However, throughout the growing year they have been savagely infested with oleander aphids, which have damaged flowerheads and made a general mess of things with their droppings. I've hosed them multiple times, but in a few days just as many are there. Since these are plants for pollinators, I cannot use insecticides on them. I'm thinking of moving them farther from our sidewalks and near-house gardens and let nature take its course, but I thought that first I would ask if there is a relatively simple remedy that gets rid of the thousands of aphids and won't harm other insects. I haven't found one online, so will look forward to your reply. Thank you. Bob Nixon, HoCo MG.###
You can spray the aphids with horticultural soap. There is less chance of burning than with horticultural oil. However, spray in the early morning when the plant is at the peak of hydration and do not spray when it is too hot. Read the label.